Pressurized fluid compressor elements are used in various settings. For example, a self-contained breathing apparatus (SCBA) typically includes an air compressor element that is used to provide safe, clean air to an individual for breathing. An SCBA is configured to be worn by individuals, such as rescue workers, firefighters, and others, to provide breathable air in a hazardous or otherwise unsafe atmosphere. When configured for use underwater, an SCBA is typically referred to as a self-contained underwater breathing apparatus (SCUBA).
SCBAs and various other fluid compressor elements may be charged or filled through the use of an air compressor. The process of compressing air to a suitable pressure that may recharge an SCBA compressor element is generally performed in four or five stages. An intercooler may be disposed between each stage. The intercooler is used to remove heat generated through the compression process.
A condensate separator is used to remove water drawn into the compressor, such as caused by humidity in the air. After a predetermined period of operation, the accumulated water is expelled from the system. For example, a drain or dump valve plumbed to each of the separators opens an exit path to the atmosphere that allows the air pressure in each separator to expel the water. In known air compressor assemblies, the drain valve is pilot operated by a solenoid valve that uses low pressure air from the compressor second stage to open the passage. Typically, the drain valve is either activated via a manual signal at the discretion of an operator, or through a timer. In each case, a prediction is made as to how often to open each drain valve. If the drain valves are operated too often, compressed air energy is needlessly wasted. Conversely, if the drain valves are not activated enough, the compressor may be damaged, such as through retained water leaking onto or into internal components.
In general, the amount of condensate water is influenced by the local air humidity during compressor operation so that a compressor used in Florida, for example, accumulates condensate quicker than one operated in Nevada. Therefore, relying on a timer to activate the drain valves may not be sufficient in high humidity environments, and inefficient in low humidity environments.